Matt Prater missed a 43-yard field goal attempt with 4 seconds to go, then got another chance because of a delay-of-game penalty. He nailed that one from 48 yards, giving the Detroit Lions (6-2) a second straight comeback victory, 22-21 over the Atlanta Falcons (2-6). Detroit trailed 21-0 at halftime Sunday at Wembley Stadium in the earliest start in NFL history.

“I knew Prater was going to make it. I played two years with him before,” Lions cornerback Cassius Vaughn said. “When he missed the first one I was like, ‘That was just the practice swing.’ The second one was cake.”

Prater’s winning kick was the first made field goal from between 40 and 49 yards this season for Detroit. If not for the penalty, it wouldn’t have happened because he went wide right on the first attempt.

“I was just like, ‘Dang it,’ and then I started looking and going, ‘Oh, oh, OK,’” Lions receiver Jeremy Ross said. “I was just like waiting to see what happened. Is he getting another kick or what? When he made it, it was fire.”

Matthew Stafford led the way for Detroit with 325 passing yards and two touchdowns. Those two scores gave Stafford 120 touchdown passes, a Lions record, two more than Hall of Famer Bobby Layne.

But it was Falcons quarterback Matt Ryan that looked like he would be the star in the first half, completing 14 of 17 passes for 160 yards and two touchdowns. Clock management problems, a penalty and a dropped pass doomed the Falcons at the end, however. Ryan finished with 228 yards and threw an interception in the second half.

The Falcons had the ball and control of the game at the two-minute warning, but couldn’t run off much time after a holding penalty and Julio Jones’ drop. Atlanta punted with 1:38 to go.

With the ball on the Detroit 7, Stafford hit Golden Tate for 32 yards. The Lions got another first down on a pass to Theo Riddick for 20 yards, and Stafford later threw to Ross for another first down.

As the clock wound down, it came down to Prater, something Detroit would have rather avoided.

From beyond the 40 and inside the 50, Detroit had been 0 for 7, and Prater, the team’s third kicker already, was 0-1.

The win was Detroit’s second comeback win in two weeks. The Lions rallied to beat the Saints last Sunday.

For the Falcons, the blown halftime lead was tied for the biggest in Atlanta history. And the Falcons have now been outscored 70-7 in the fourth quarter their last six games.

“This is as tough a loss to take as any that I’ve ever been a part of,” Ryan said. “We had a lot of chances to win that ballgame. It’s just that we didn’t make plays when we needed to.”

Both teams have a bye next week, giving each time to get healthy. The Lions hope star receiver Calvin Johnson will be back to face Miami on Nov. 9. Johnson has missed three straight wins since aggravating his right ankle injury on Oct. 5.

Prater kicked a 22-yard field goal in the third quarter, and Tate made it 21-10 with a 59-yard reception from Stafford.

In the fourth quarter, Prater kicked a 20-yarder and Stafford later hit Riddick for 5 yards and another touchdown to make it 21-19. Detroit went for 2, but Stafford’s pass eluded Tate.

The Lions came in with the league’s top-ranked defense, but Ryan picked it apart early with relative ease. He completed 5 of 6 passes on the opening drive for 64 yards, culminating in a 7-yard touchdown pass to running back Devonta Freeman.

Later in the first quarter, Ryan hit Bear Pascoe from the 1 and it was 14-0. The touchdown came one play after a 20-yard pass interference call when Darius Slay impeded Roddy White in the end zone.

Steven Jackson also scored for Atlanta (2-6), running in from the 1 moments after becoming the 19th player in NFL history to rush for 11,000 yards.

“It felt good in the first half, we were hitting and stopping them,” said Falcons cornerback Desmond Trufant. “Then the second half, I don’t know what happened. We didn’t put our foot on the gas.”

Sunday was the second of three regular-season NFL games this year at Wembley, the home of England’s national soccer team. Miami beat Oakland 38-14 on Sept. 28, and Dallas will face Jacksonville on Nov. 9.

The game started at 1:30 p.m. in the British capital, which is 9:30 a.m. on the East Coast and 6:30 a.m. on the West Coast.

NOTES: Stafford is also one of only three quarterbacks since 1966 to overcome 21-point deficits three times as a starter. Tom Brady and Drew Bledsoe are the others, according to the Lions. … LaAdrian Waddle was inactive for Sunday’s game, one week after getting a concussion late in the comeback win over the Saints. Although Waddle was injured on an extra point attempt, he was on the field for the final play of the game when Stafford took a knee.